code: def get_backend(name):
      return _scheme_to_backend_cls[name]
  
file_path: mars/mars/oscar/backend.py
imports: from abc import ABC, abstractmethod
  from typing import Dict, Type
  from .context import register_backend_context
  from .driver import register_backend_driver
label_desc: Use image node_id 2 for calling a global function with example usage: get_backend(name) and returns: _scheme_to_backend_cls